Senior Systems Administrator

Are you a hands-on Systems Administrator who enjoys solving complex infrastructure problems and working across a variety of client environments?

We’re looking for a Senior Systems Administrator to join a growing managed IT services provider supporting clients across the Greater Toronto Area. This is a hands-on role with a strong focus on virtualization, Microsoft 365, Azure, and networking .

The ideal candidate has strong infrastructure experience, is comfortable working directly with clients, and can take ownership of technical issues from troubleshooting through to resolution.

Work Type: 

• Fully Onsite - 5 days a week in-office or visiting client sites; on-call and after hours support when required

• Location:  Toronto, ON

• Work Type:  This is a newly created position

Requirements

What You’ll Do: 

• Manage and troubleshoot virtualized infrastructure , including Nutanix HCI environments
• Administer and support Microsoft 365 environments, including Exchange Online, SharePoint, Teams, OneDrive, and user/license management
• Support Azure and Entra ID environments, including hybrid identity and cloud infrastructure
• Configure, maintain, and troubleshoot network infrastructure , including LAN/WAN, VLANs, firewalls, VPNs, and Wi-Fi
• Serve as a senior escalation point for complex technical issues and Level 1/2 tickets
• Support server, endpoint, operating system, and infrastructure-related issues across client environments
• Lead and support infrastructure projects, including migrations, upgrades, and implementations
• Monitor system health and proactively identify and resolve potential issues
• Maintain accurate technical documentation, network diagrams, and infrastructure standards
• Work directly with clients and vendors to resolve technical issues and deliver solutions
• Provide technical guidance and mentorship to junior technicians
• Apply security best practices across client systems and infrastructure

What We’re Looking For: 

• 5+ years of experience in Systems Administration, Infrastructure Engineering, or a similar role
• Experience working within an MSP, managed services, or multi-client environment
• Hands-on experience administering Nutanix HCI , including cluster management and AHV/VM administration
• Strong experience administering Microsoft 365 , including Exchange Online, SharePoint, Teams, and OneDrive
• Experience with Azure and Microsoft Entra ID , including hybrid environments
• Solid understanding of networking , including LAN/WAN, VLANs, firewalls, VPNs, and routing
• Experience with Windows Server and on-premises Active Directory
• Experience with RMM and PSA platforms; HaloPSA and NinjaOne are an asset
• Strong troubleshooting and problem-solving skills
• Experience mentoring, coaching, or providing technical direction to junior technicians
• Strong client-facing communication skills and the ability to work with both technical and non-technical stakeholders
• Strong organizational skills and the ability to manage multiple client environments and competing priorities

Nice to Have

• Cybersecurity experience from a systems/infrastructure administration perspective
• Experience with SentinelOne, Microsoft Defender, or other EDR/MDR platforms
• FortiGate or other firewall experience
• Microsoft 365 security experience, including Conditional Access, MFA, Intune, and DLP
• Experience with infrastructure migrations to Azure/Microsoft 365
• ITIL Foundation or working knowledge of ITIL practices
• Experience supporting law firms or professional services organizations
• Experience with operational technology (OT), building automation, or commercial property environments
• Nutanix or Microsoft certifications

What Makes This Role Exciting? 

• Technical Variety: Work across virtualization, cloud, Microsoft 365, networking, and infrastructure
• Client Exposure: Work directly with a diverse client base and become a trusted technical resource
• Hands-On Environment: Take ownership of real infrastructure challenges and projects

• Technical Growth: Continue developing your expertise across modern infrastructure and cloud technologies

• Leadership Opportunity: Mentor junior technicians and play a key role in supporting the broader technical team

Benefits

• Base Salary: $90,000 - $120,000
• Performance Bonus Eligibility
• Paid Time Off & Extended Health Benefits (Medical/Dental/Vision)
• Professional development, training, and certification opportunities

Ready to Elevate Your Career? Apply Now! 

At STACK IT Recruitment , we connect top talent with standout opportunities. If you meet at least 70% of the qualifications, we encourage you to apply, we’d love to chat!

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We’re committed to diversity and inclusion. Need accommodation during the hiring process? Let us know, we’re here to support you!

AI Use Disclosure

STACK IT uses AI-enhanced tools to support initial candidate screening and interview note analysis. All assessments and hiring decisions remain human-led.